Background: The predictive role of human epidermal growth factor receptor 2 (HER2) to adjuvant anthracycline-based chemotherapy remains controversial. Here, we investigated the association between HER2 status and pathological response in breast cancer patients who received neoadjuvant anthracycline-based regimens.
Patients and methods: Women (n = 538) with operable primary breast cancer received neoadjuvant anthracycline-based chemotherapy. Pathological complete response (pCR) was defined as no invasive breast tumor cells in breast after completion of neoadjuvant chemotherapy. HER2 status was determined by immunohistochemistry and/or by fluorescence in situ hybridization in core biopsy breast cancer tissue obtained before initiation of neoadjuvant chemotherapy.
Results: In this cohort of 538 patients, 23.9% of patients achieved a pCR in their breast. HER2-positive tumors had a lower rate of pCR than did HER2-negative tumors (14.7% versus 25.7%, P = 0.013); negative HER2 status remained as an independent favorable predictor of pCR after adjusted for age, estrogen receptor, progesterone receptor, tumor size, chemotherapy cycles, and tumor grade in a multivariate analysis (odds ratio = 3.14; 95% confidence interval = 1.60-6.16, P = 0.001). Furthermore, patients with a pCR had a higher 3-year disease-free survival (DFS) rate than did patients without a pCR (P = 0.007).
Conclusion: Women with HER2-negative breast cancers rather than HER2-positive tumors benefit from anthracycline-based neoadjuvant chemotherapy.